A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustor section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors and the turbine section includes low and high pressure turbines.
A nacelle surrounds the engine. An inlet section of the nacelle is that portion of the nacelle that is forward of the fan section of the engine. One function of the inlet is to reduce noise. A minimum length of the inlet is typically required for noise reduction with high bypass ratio engines.
While longer inlets tend to improve noise reduction, that feature does not come without cost. A longer inlet is associated with increased weight and external drag. Additionally, the airflow at the inlet during takeoff typically creates a bending moment that is proportional to the length of the inlet. Longer inlets, therefore, tend to introduce additional load on the engine structure under such conditions.